Hamilton young castner



- (No Model.)

H. Y. GASTNER. v PROCESS OF AND APPARATUS FOR MAKING ALKALI GYANIDS. No.543,643.

Patented T111130, 1895.

] WITNESSES.

UNITED STATES PATENT OFFICE.

HAMILTON YOUNG OASTNER, OF LONDON, ENGLAND.

PROCESS OF AND APPARATUS FOR MAKING ALKALI CYANIDS.

SPECIFICATION forming part of Letters Patent No. 543,643, dated July 30,1895.

Application filed November 20,1394. Serial No. 629,387. on model) To allwhom it may concern:

Be it known that I, HAMILTON YOUNG CAST- NER, a citizen of the UnitedStates, residing at London, England, have invented a certain new anduseful Improvement in the Manufacture of Alkali Oyanids; and I do herebydeclare that the following is afull, clear, and exact description oftheinvention, which will enable others skilled in the art to which itappertains to use the same.

In two patent applications filed on July 5, 1894, I have described andshown a method for the production of alkali cyanid by employing thealkali metal as a starting point and combining same with either nascentor combined nitrogen and carbon, (either in the nascent state or in oneof its ordinary forms,) the nitrogen being either in the nascent stateor nitrogen combined with a certain quantity of hydrogen being producedby the decomposition of anhydrous ammonia. In carrying on the saidprocesses while the ultimate product is alkali cyanid severalintermediate re actions take place and these at times render itdiflicult to carry on the manufacture without considerable care to avoidloss of nitrogen. I have found by experiment that such loss can beavoided if I carry on the process in two separate steps or reactions.Thus a product closely approaching the theoretical yield from the amountof alkali metal and ammonia employed can be obtained and the generalcharacter of the process will be much simplified. In this manner theprocess may either be carried on continuously or intermittently. Briefiy stated, therefore, the present invention while depending upon the sameprinciple as to the employment of the alkali in the metallic formparticularly relates to carrying on the process in two steps, whereby anintermediate product is actually obtained and which is then directly andseparately converted into alkali cyanid. The first step of the processconsists in passing anhydrous ammonia over metallic sodium heated to atemperature of between 300 and 400 centigrade and thereby producing amidof the alkali metal, the reaction being NH,+Na=NaNH,+H. The second stepis the fusing of the protemporarily stopped.

duct in contact with carbon and so forming the alkali cyanid, thereaction being In the accompanying drawings I show a form of apparatuswell adapted for carrying out the manufacture.

Figure l is a sectional elevation of the furnace A, in which is set therectangular iron retort B, having an inclined bottom. Fig. 2 is ahorizontal section of the upper half of the iron retort; Fig. 3, asection of the retort through the line my in Fig. 1, and Fig. 4 is avertical iron retort in which the second step of the process is carriedon.

The upper half of the retort B is provided with partitions O, whichreach down so as to project into the bath of molten alkali metal D.Opposite ends of these partitions are cut away, as shown in Fig. 2, soas to compel the passage of any vapor or gas to take the direction shownby the arrows. The upper half is furthermore provided with a branchedinletpipe L, an outlet-pipe M, and a swan-neck inlet-pipe and hopper N,which is also provided with a valve 0. Thebottom half of the retort isprovided with partitions E and F, the former rising above the level ofthe latter and the partition H, which rises above the level of F andwhich partition has several openings at the bottom. (Shown at K.) Thebottom is furthermore provided with an outlet-pipe P and a swan-neckoutlet-pipe B.

Fig. 4 shows a vertical iron retort S set in furnace T. This retort isprovided with a funnel entranee'pipe U, a hopper V, a gas-outlet pipe W,and a swan-neck outlet-pipe Z.

In carrying on the process the retort, Fig. 1, is raised to atemperature of between 300 and 400centigrade. .Perfectly-dryammoniagasis then allowed to enter through the pipes L and L in order to expel theair. Metallic sodium,which is melted in N,is then allowed to flow inuntil it rises to the level of the dotted line between E and H and,overflowing at F, it passes out through B, when the supply is The flowof ammoniagas is now regulated to the ascertained capacity of the retortand the proportionate quantity of sodium introduced through N atintervals-that is, for every seventeen pounds ICC) of ammonia-gasintroduced twenty-three pounds of sodium must be added. The amid formingon the surface of the molten sodium melts, sinks to the bottom, flowingalong the same, and gradually fills the space between H and F, expellingthe sodium through the pipe R. The overflow of amid then becomes regularand may be collected in closed vessels for future treatment with carbon,or it may be allowed to flow directinto the retort S through the openingU. This retort having been heated to dull redness and filled withcharcoal through the hopper V, the reaction here taking place produceshydrogen and eyanid, the former escaping through the opening \V, whilethe latter fuses, filters through the bed of charcoal, andescapesthrough the opening Z into receptacles placed for its reception.Fresh carbon is introduced from time to time to replace that'used in theformation of the eyanid. The gas escaping from the pipe M will consistof hydrogen, together with a small quantity of ammonia, and is ledthrough acid, when the latter is absorbed for re-use.

In stopping the apparatus some care is necessary owing to the presenceof hydrogen. The inlet-pipe N, Fig. 1, is closed by the tap O, and whilethe ammonia is still passing the charge of molten sodium and amid isdrawn off through the pipe P. This is then closed and either nitrogen orcarbonic-acid gas admitted through L" L, while L L is closed in order tosweep out all the ammonia and hy drogen. It is thus possible to obtainpure alkali cyanid practically in one continuous operation, although bytwo separate and distinct reactions.

I am quite aware that it is not new to form an amid by passing ammoniaover an alkali metal, although such an operation had no commercialapplication and was merely of scientific interest.

I am aware that the description in Felilings Neues I-Zandworierb'uch derChem'ie, vol. 4, page 695, states that sodium amid has been formed byheating metallic sodium with dry ammonia with exclusion of air, and alsothat sodium amid has been heated with eharcoal with the formation ofcyanid and hydrogen; but so far as I am aware it has not heretofore beenproposed to commercially manir facture alkali cyanid by first making anamid and then decomposing the same in the presence of preheated carbon.

It is evident that in place of carbon it is quite possible to heat theamid in an atmosphere of hydrocarbon to form the cyanid, and in place ofan alkali metal being used an alkali alloy may be substituted.

llavin g now particularly described and ascertained the nature of thesaid invention and in what manner the same is to be performed, I declarethat what I claim is- 1. The improvements in the manufacture of alkalicyanids consisting in first producing an amid by decomposing anhydrousammonia in the presence of an alkali metal maintained at a temperatureas set forth and then converting the amid into cyanid by decomposing itin the presence of carbon heated previously to the admission of theamid,as described.

2. lhe improvements in the manufacture of alkali cyanids consisting inintroducing molten alkali metal at atemperature of about 300 to 400centigrade into an atmosphere of anhydrous ammonia in the proportions ofabout twenty-three pounds of alkali metal for each seventeen pounds ofammonia gas, withdrawing the amid produced and decomposing it by passingit through carbon heated to redness previously to the admission of theamid and collecting the resulting cyanid.

3. In apparatus for the manufacture of alkali cyanids an externallyheated retort provided with gas inlet and discharge pipes and inletpipes for the molten alkali metal, means for causing the gas to comeintointimate contact with the metal and means for drawing off the amidproduced.

4. In apparatus for the manufacture of alkali cyanids an externallyheated retort provided with baffle plates dipping into the molten metalan end plate with bottom openings through which the produced amid passesand an overflow plate and discharge pipe for same.

In testimony whereof I have hereunto set my hand in the presence of twosubscribing witnesses.

HAMILTON YOUNG CASTNER.

Witnesses:

G. H. CLARKSON, E. MAsON.

